JPH09219943A - Rotating electric machine - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a rotating electric machine capable of sufficiently improving performance and reducing size and weight by using a split core type stator. SOLUTION: A stator core 3A of a rotary electric machine is divided into an L-shaped core piece 31 and a rod-shaped core piece 32, and then formed by combining a predetermined number of these pieces. A joint surface S of the core-shaped core pieces 31 is inclined by a predetermined angle θ from a surface perpendicular to a magnetic flux flowing direction indicated by an arrow φ, that is, a radial surface passing through the axis O. [Effect] Since the joining area increases due to the slanting, it is possible to suppress an increase in the magnetic resistance due to the air gaps existing in the joining surface, and as a result, the advantages of using the split core type stator are surely obtained. It is possible to make full use of the improved performance and the reduction in size and weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine such as an induction motor or a synchronous machine, and more particularly to a rotating electric machine suitable for a relatively small-capacity general-purpose induction motor.

[0002]

2. Description of the Related Art A rotary electric machine having a relatively small capacity, such as a general-purpose induction motor, has a structure shown in FIG. In FIG. 6, reference numeral 1 denotes a housing, which is also called a frame or a frame, and is formed into a substantially cylindrical shape by casting an iron-based material such as cast iron, and constitutes a casing of the electric motor. Reference numeral 1a denotes a heat radiation fin, which is in the form of a strip extending in the axial direction, is integrally cast with the housing 1, and is radially formed on the outer periphery thereof.

2A and 2B are end brackets, which are also called bearing brackets, in which the bearings 4A and 4B are housed and are fitted to both ends of the housing 1 by spigot fitting.

As shown in FIG. 7, a stator 3 is a stator core 3A made of a laminate of annular silicon steel plates (electromagnetic steel plates) having a plurality of slots 3C on the inner peripheral side. The stator winding 3B is wound inside the slot 3C of the iron core 3A.

A rotor 5 has a rotary shaft 6, and the rotary shaft 6 is rotatably held by bearings 4A and 4B of the end brackets 2A and 2B so that the rotor 3 can be rotated at a predetermined position in the stator 3. , Is configured to rotate at a position facing the stator 3.

In such a conventional motor, the stator 3 is inserted into the housing 1 in advance and attached to the inner peripheral wall thereof, and then the rotor 5 is inserted into the stator 3.
Then, the bearings 4A and 4B are fitted to the rotating shaft 6, and the end brackets 2A and 2B are fitted to both ends of the housing 1 by spigot fitting, respectively.
(Not shown), it is fixedly attached to the housing 1 and assembled.

The rotating shaft 6 has one end (the right side in the figure) inserted through the bearing 4B of the end bracket 2A and protrudes to the outside to form an output shaft, while the other end (the same, left side) is an end. An external cooling fan 9 (hereinafter, referred to as an external fan) is attached to a portion of the bracket 2A protruding from the bearing 4A.

Reference numeral 10 denotes an end cover, which forms a cover for covering the outer fan 9. And this end cover 10
The opening 10a for taking in outside air with the outside fan 9
(Hereinafter referred to as the ventilation inlet). The opposite side of the opening 10a is formed in an open cylindrical shape or an irregular cylindrical shape, so that a radial gap 10b is formed between the end bracket 2A and the outer diameter portion of the housing 1.
A ventilation outlet consisting of is formed.

Therefore, when the outer fan 9 is rotated by the rotor 5, outside air is sucked in from the ventilation inlet 10a of the end cover 10 and blown out from the gap 10b, whereby the end bracket 2A and the housing 1
And ventilating outside air to the outer surface of the end bracket 2B,
A cooling effect is obtained.

As described above, the rotor 5 is mounted in the housing 1 of the rotating shaft 6 at a position facing the stator 2. The rotor 5 has a secondary conductor bar (not shown) , An end ring 7, and an internal cooling fan 8 (hereinafter referred to as an inner fan) integrally formed with the end ring 7.

The inner fan 8 is composed of a plurality of blades protruding from both end surfaces of the end ring 7 in the axial direction to circulate air inside the electric motor so as to obtain a cooling effect. That is, the air flow generated by the inner fan 8 passes through the rotor 5, the end ring 7, the stator windings 3B, and both end faces of the stator core 3A while being cooled, and is relatively compared with the housing 1. When passing along the inner surfaces of the end brackets 2A and 2B having a low temperature rise, heat can be dissipated.

Incidentally, as a technique relating to this kind of prior art, for example, JP-A-61-251440 can be cited.

By the way, in such a rotary electric machine, miniaturization and weight reduction have always been a major proposition, but the miniaturization of the rotary electric machine tends to deteriorate the characteristics, and particularly the output and the stall torque (maximum torque). ) Tends to decrease. However, in order to prevent these decreases, if the number of windings of the stator coil (armature coil) is increased and the magnetic flux density is increased, there is a problem that iron loss increases and power factor and efficiency deteriorate. It was

In general, in order to make a rotary electric machine small,
It is effective to reduce the size of the stator, but in this case, in order to reduce the outer diameter of the stator and output the same torque, the magnetomotive force must be maintained at the same value. That is, it is necessary to configure the rotating electric machine without changing the magnetic load. In other words, it is important to keep the amount of magnetic flux per unit area of the stator (hereinafter referred to as magnetic flux density) constant without reducing the amount of magnetic flux generated in the stator.

However, in this state, the amount of magnetic flux remains the same as it was before miniaturization, and only the stator becomes smaller, resulting in an increase in magnetic flux density, which in turn causes magnetic flux saturation, resulting in deterioration of the characteristics of the rotating electric machine. Resulting in. Therefore,
Even if the stator becomes smaller, the magnetic flux density does not saturate,
In order to configure without changing the magnetic loading, it is necessary to secure the area of each magnetic path portion of the stator to be equal to that before the miniaturization. As a result, the slot area of the stator is reduced, so that the stator winding 3B is inserted in the slot.
Can no longer be stored.

In the prior art, this is the stator winding 3B.
Are inserted into the slots 3C one by one from the opening grooves, so that the stator windings 3 are not inserted in the slots 3C.
Since the arrangement of B is irregular, the storage volume of the coil is not comparable to the slot volume, and the volume ratio (hereinafter referred to as the space factor) remains in the 60% range, and the coil storage limit is limited. Because there is.

Therefore, in order to improve the space factor, there has been conventionally known a split iron core type rotary electric machine in which a stator iron core is divided to improve the coil storability. This split-core-type rotating electric machine uses a stator iron core divided into a predetermined number and sequentially assembles these into a preformed stator winding to assemble the stator. Since it is not necessary to insert the coils one by one into the slots of the child iron core and perform winding, it is possible to fill the coils with no gaps in the slots, and as a result, a sufficient space factor improvement can be obtained. The size can be reduced.

[0018]

The above-mentioned prior art does not pay particular attention to the increase in magnetic resistance due to the division of the stator core, and the performance improvement of the rotary electric machine is improved by using the divided core type stator. I was dissatisfied with the points. It is an object of the present invention to provide a rotating electric machine that makes it possible to sufficiently improve performance and reduce the size and weight by taking advantage of the split core type stator.

[0019]

In the rotary electric machine in which the stator core is formed by a combination of a plurality of laminated core pieces, the stator iron core cylindrical yoke portion of the laminated core pieces is formed. The joint surface at the portion is achieved by being configured by a plane inclined at a predetermined angle from a plane perpendicular to the magnetic flux passing direction in the cylindrical yoke portion.

Here, if the plane perpendicular to the passing direction of the magnetic flux is inclined, the area becomes larger than the area of the original plane.

By the way, as is well known, the magnetic resistance in the magnetic circuit is inversely proportional to the cross-sectional area of the path and is proportional to the length, like the electric resistance in the electric circuit. On the other hand, the joint surface of the laminated core piece acts as a magnetic circuit having its area as the magnetic flux distribution cross-sectional area and the air gap existing therein as the magnetic flux distribution length, so the magnitude of the magnetic resistance given by it is: It is inversely proportional to the area of the joint surface and proportional to the length of the void.

Therefore, if the joint surface is inclined from the plane perpendicular to the magnetic flux passing direction, the area becomes large,
The magnetic resistance can be reduced, and as a result,
It is possible to minimize the increase in magnetic resistance due to the division of the stator core.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A rotating electric machine according to the present invention will be described in detail below with reference to embodiments. One embodiment of the present invention is an induction motor, but the overall configuration is the same as the conventional induction motor described in FIG. 6, and different points are as follows.
Since only the stator core 3A has a split core shape, the configuration of the stator core 3A will be mainly described below.

FIG. 1 shows a stator 3 according to an embodiment of the present invention, which comprises a split type stator core 3A and a stator coil 3B housed in a slot 3C thereof. There is. As shown in the figure, the stator core 3A is divided into two types, an L-shaped core piece 31 (first laminated core piece) and a rod-shaped core piece 32 (second laminated core piece). Then, a plurality of L-shaped iron core pieces 31 are sequentially arranged in an annular shape and combined with each other, while a rod-shaped iron core piece 32 is
The stator core 3A is configured by inserting the L-shaped iron core piece 31 into the notch on the inner circumference of the slot space portion substantially outwardly from the central axis O of the stator core 3A and combining them. ing.

Here, as shown in FIG. 3A, the L-shaped iron core piece 31 has a back portion 3 having a proper width in the circumferential direction of the stator.
1a, one end surface side of the back portion 31a, a right end surface side in the figure, a tooth portion 31b protruding toward the central axis O direction of the stator core 3A, and a tooth portion 31b provided on the left side of the tooth portion 31b. Further, it is formed in a shape having a notch portion 31c forming a space portion for the slot and a notch portion 31d having a width substantially similar to the tooth portion 31b on the left side of the inner periphery of the space portion notch 31c.

At this time, the end faces 31e, 31f in the circumferential direction of the core piece back part 31a are not parallel to the straight line shown by the chain line passing through the central axis O of the stator core 3A, but are inclined by a predetermined angle θ. Is formed.

Next, as shown in FIG. 3 (b), the rod-shaped core piece 32 has a root portion 32a at one end and a tooth portion 32b at the other end, and at the tip of the tooth portion 32b. The rod-shaped iron core is formed in a rod shape having a tongue piece 32c that forms a slot opening, and when the root portion 32a is radially inserted into the notch 31d in the inner space of the slot space portion of the L-shaped iron core piece 31, A slot 3C for housing the stator coil is defined between the tooth portion 32b of the piece 32 and the tooth portion 31b of the L-shaped iron core piece 31.

Therefore, the back portion 31a of each L-shaped iron core piece 31
The dimension in the circumferential direction is such that when the rod-shaped core piece 32 is inserted and engaged, the tooth portion 31b adjacent thereto forms a space portion of the slot 3C having a predetermined dimension. .

The L-shaped iron core piece 31 and the rod-shaped iron core piece 32 are formed by laminating a predetermined number of iron plates punched from an electromagnetic steel plate such as a silicon steel plate into a planar shape as shown in FIG. The faces are laser welded and integrated, for example.

Therefore, the L-shaped iron core piece 31 and the rod-shaped iron core piece 32 are used to assemble the L-shaped iron core piece 31 into a tubular shape with the respective end faces 31e and 31f abutted against each other, and the inner surface thereof. When the rod-shaped core pieces 32 are combined with each other and combined with the stator coil 3B, the stator 3 is configured. Therefore, for this reason, the stator coil 3B can be stored in the slot 3C in advance.
It is molded into a predetermined shape.

According to the stator 3 thus constructed, the magnetic resistance at the joint surface between the end faces 31e and 31f of the L-shaped core piece 31 of the stator core 3A can be minimized. , As a result, the decrease in the number of magnetic fluxes due to the division of the iron core can be sufficiently suppressed.
The reason will be described.

First, the back portions 31a of the L-shaped core pieces 31 forming the stator core 3A are mutually end faces 31e and 31f.
Are assembled in a tubular shape in a state where they are butted against each other to form a yoke portion (yoke portion) of the stator core 3A. Therefore, the magnetic flux in the back portion 31a of the L-shaped iron core piece 31 flows through the joint surface between the end surfaces 31e and 31f in the circumferential direction with the axis O as the central axis, as indicated by the arrow φ.

On the other hand, the L-shaped core piece 31 of the stator core 3A
The end faces 31e and 31f of the are inclined at an angle θ from the plane perpendicular to the direction of the magnetic flux indicated by the arrow φ, and as a result, the magnetic flux indicated by the arrow φ is
The joint surface formed by these end surfaces 31e and 31f has a larger area than the plane perpendicular to the magnetic flux passage direction, and therefore the magnetic resistance due to the joint surface can be minimized.

Therefore, by constructing the induction motor shown in FIG. 6 using the stator 3 shown in FIG. 1, the advantages of using the split core type stator can be fully utilized.
A high-performance, small-sized and lightweight rotating electric machine can be easily obtained.

Next, the above embodiment will be described in more detail. First, as the stator coil 3B, an ordinary conductor having a circular cross-section may be used, but as shown in FIG. 4, for example, a conductor 33 having a substantially rectangular cross-section is used, and the conductor 33 in the slot 3C is used. As shown in the drawing, it is desirable to arrange the long side portions in the longitudinal direction of the slot 3C and the short side portions in the lateral direction of the slot 3C.

According to this, the space left between the conductors 33 can be minimized, and the space between the conductors 33 and the inner wall of the slot can also be minimized. As a result, The space factor can be further improved. In addition,
In FIG. 4, a slot liner 34 is mounted on the stator coil 3B.

Next, a method of assembling the stator 3 shown in FIG. 1 will be described. First, when the stator 3 is assembled, a predetermined number of preformed stator coils 3B are annularly arranged and held at a predetermined position at a predetermined angle by a jig (not shown), and then, as shown in the drawing. The rod-shaped iron core piece 32 is moved from the inner peripheral side with respect to this stator coil by means such as an index and a collet chuck, and the stator coil 3B is positioned on both sides of the rod-shaped iron core piece 32.

After that, the L-shaped iron core piece 31 is moved from the outer peripheral direction by a moving means such as an index (not shown), and the bar-shaped iron core piece 32 is placed in the notch 31d.
By inserting and engaging, the stator coil 3B can be housed in the slot 3C defined by the tooth portion 31b of the iron core piece 31 and the tooth portion 32b of the rod-shaped iron core piece 32.

Therefore, the preformed stator coil 3B is used.
Since the stator coil 3B can be housed in the slot 3C simply by assembling the L-shaped iron core piece 31 and the rod-shaped iron core piece 32, which are formed separately, the stator coil 3B can be housed properly.

Therefore, it is not necessary to press the stator coil 3B into the slot as in the prior art,
A large number of the conductors of the stator coil 3B can be accommodated in the slot 3C to the maximum extent.

Moreover, the notch 31 of the L-shaped core piece 31
Since the stator 3 can be formed by moving the rod-shaped core piece 32 in the radial direction from the center side of the stator 3 with respect to d and inserting and engaging it, the stator coil composed of a large number of conductors is press-fitted into the slots. In comparison with the prior art, the stator coil can be stored very easily, resulting in the slot 3
Despite the miniaturization of the area of C, the coil space factor in the slot can be reliably increased.

Further, in the prior art, a groove having a slight width is provided on the inner circumference of the stator core to guide the coil into the slot 3C.
Since it is designed to be stored, the width of this groove is dominated by the diameter of one of the coil conductors.
In order to improve the characteristics of the rotating electric machine, there is a limitation in arbitrarily selecting the groove width.

In the above embodiment, however, the stator coil 3B can be housed by inserting and engaging the rod-shaped core piece 32 into the L-shaped core piece 31, so that the groove width is limited as in the prior art. Will be eliminated, and the design latitude of the rotating electrical machine will be increased, and it will be possible to design the optimum.

Further, as shown in FIG. 3 (b), a tongue piece 32c is formed at the tip of the tooth portion 32b of the rod-shaped iron core piece 32, and the tongue piece 32c forms an opening narrower than the width of the slot 3C. Therefore, not only can the conductor of the stator coil 3B be prevented from coming out of the slot 3C to the outside, but also the teeth of the L-shaped core piece 31 circumferentially adjacent to the tongue piece 32c. Since the gap with the portion 31b can be made small, noise generated when the rotor 5 rotates can also be reduced.

Next, FIG. 5 shows another embodiment of the stator core 3A. This stator core 3A is different from the L-shaped core piece 31 described in FIG. Using the L-shaped iron core piece 31 ', this L-shaped iron core piece 31'
Are alternately laminated in the axial direction with the L-shaped iron core pieces 31.

According to the stator core 3A of FIG. 5, the engaging portions of the core pieces do not lie on the same line when viewed in the stacking direction, but are arranged in the circumferential direction while intersecting each other. It is possible to obtain the effect that the laminated state of is solid.

[0047]

According to the present invention, an increase in the magnetic resistance due to the division of the stator core can be minimized with a simple structure in which the joining surface of the stator core is tilted.
Utilizing the advantages of the split core type stator, it is possible to sufficiently improve the performance of the rotating electric machine and reduce its size and weight.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a stator in an embodiment example in which the present invention is applied to an induction motor.

FIG. 2 is a front view of a stator core according to an embodiment of the present invention.

FIG. 3 is an exploded explanatory view of a stator core according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an example of a stator coil according to the embodiment of the present invention.

FIG. 5 is a front view of a stator core according to another embodiment of the present invention.

FIG. 6 is an explanatory diagram of an induction motor that is an example of a rotating electric machine.

FIG. 7 is a plan view of a stator core in a conventional example of a rotating electric machine.

[Explanation of symbols]

 1 Housing 3 Stator 3A Stator core 3B Stator coil 3C Slot 31 L-shaped core piece 31a Back part 31b Tooth part 31c Notch part for slot 31d Notch part 31e, 31f Circumferential end face 32 Rod-shaped core piece 32a Back part 32b tooth 32c tongue

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tsukio Sekine, 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Izumi Shimizu 4-6-Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. In-house (72) Inventor Yukio Endo 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Matsuri 4--6 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Ryuichi Iwata 4-6, Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Takahiro Takeda 7-1 Higashi Narashino, Narashino, Chiba Prefecture Industrial Equipment Division, Hitachi Ltd.

Claims (2)

[Claims] 1. A rotating electric machine in which a stator core is formed of a combination of a plurality of laminated core pieces, wherein a joint surface of the laminated core piece at a portion forming a stator core cylindrical yoke portion is A rotating electric machine comprising a plane inclined at a predetermined angle from a plane perpendicular to a magnetic flux passage direction in a cylindrical yoke portion. 2. The invention according to claim 1, wherein the laminated core piece has two different shapes of a first laminated core piece and a second laminated core piece, and the first laminated core piece is the It has a shape required to form a cylindrical yoke portion, a tooth portion for forming a magnetic pole, a space portion for forming a slot, and a cutout portion for inserting a root portion of the second laminated core piece. The second laminated core piece is formed in a shape necessary for forming a tooth portion for forming a magnetic pole and a root portion to be inserted into the cutout portion of the first laminated iron core. And rotating electrical machinery.